1. Field of the Invention
This invention relates to a recording apparatus for recording information included in an electro-magnetic radiation-beam applied thereto and a recording head used for the same.
2. Description of the Prior Art
A recording apparatus for recording information included in an electro-magnetic radiation-beam applied thereto are known, which comprises a recording medium including a color-separation filter and a recording layer. A recording head used for the recording apparatus comprises a photoconductive layer having a carrier transport layer and a carrier generation layer, an electrode layer, and a base layer which are laminated in order of mention. Such prior art recording apparatus and the recording head are disclosed in Japanese patent application No. 1-128069.
Hereinbelow will be described this prior art recording apparatus and recording head with reference to drawings.
FIG. 8 is a perspective view showing the prior art recording apparatus and recording head wherein a photoconductive layer 22 and a recording layer 12 separated are shown.
In FIG. 8, a recording medium 10 capable of formation of a latent charge image, comprises the recording layer 12, a transparent electrode layer 14, a color separation filter layer 16, and a glass base layer 18, which are laminated in order of mention.
The recording head 20 comprises the photoconductive layer 22 including a carrier transport layer 22b and a carrier generation layer 22a, an electrode layer 24, and a base layer 26 which are laminated in order of mention.
The recording medium 10 and the recording head 20 are arranged such that the recording layer 12 and the carrier transport layer 22b of the photoconductive layer 22 face each other with a given space. An optical image of an object 28 enters there through the glass base layer 18 of the recording medium 10 via the object lens 30.
In FIG. 8, a power supply 32 with a given voltage is connected between the transparent electrode layer 14 and the electrode layer 24. It generates discharge between the recording layer 12 and photoconductive layer 22.
The color separation filter layer 16 comprises thin bar-shaped filters 16R, 16G, and 16B arranged in order of mention for color-separation by transmitting primary color lights or red (R), green (G), and blue (B) by filters 16R, 16G, and 16B respectively.
A charge retaining material for retaining charges on its surface or therein and photo-modulation member whose optical characteristic varies, can be used for the recording layer 12.
Hereinbelow will be described operation of recording of the prior art.
In FIG. 8, the optical image of the object 28 enters the object lens 30 from the right of the drawing as shown by an arrow F and enters the photoconductive layer 22 of the recording head 20 through the object lens 30 and the recording medium 10.
The filters 16R, 16G, and 16B of the color separation filter layer 16 separate the incident light into three primary colors. That is, the filter 16R allows only R component of the incident light to transmit therethrough; the filter 16G, only G component, and the filter 16B, only B component. That is, the filter layer 16 performs color separation. These color-separated transmitted light beams enter the photoconductive layer 22 through the transparent electrode layer 14 and the recording layer 12.
The photoconductive layer 22 is formed by laminating the carrier transport layer 22b and the carrier generation layer 22a as mentioned above. The carrier transport layer 22b faces the recording layer 12. Thus, the color-separated light beams transmit the carrier transport layer 22b and enter the carrier generation layer 22a. The incident light beams are absorbed by the carrier generation layer 22a, so that carriers are generated in the carrier generation layer 22a. As mentioned above, the potential of the power supply 32 is applied between the transparent electrode layer 14 and the electrode layer 24. Therefore, holes of the carriers generated in the carrier generation layer 22a move through the carrier transport layer 22b to a surface of the carrier transport layer 22b opposite to the recording layer 12.
This movement produces a charge image corresponding to the optical image of the object 28 on the surface of the photoconductive layer 22.
Such operation is made for each of separated light beams of R, G, and B, so that positive charge images are formed with respect to every separated light beam.
Then, application of the given voltage of the power supply 32 generates discharge between confronting surfaces of the recording layer 12 and the photoconductive layer 22.
This discharge produces a charge Q on the surface of the recording layer 12 and is accumulated and retained on its surface. In this case, the degree of the charge due to the discharge corresponds the positive charge image accumulated. Therefore, an image corresponding to the optical image of the object 28 is transferred on the surface of the recording layer 12. In other words, an amount of a charge per unit area on the recording layer is relates to an intensity of light per the unit area.
When the charge retaining layer is used for the recording layer 12, a charge latent image corresponding to the optical image of the object 28 is recorded on the surface of the charge retaining layer of the recording medium 10. The positive charges on the charge retaining layer are produced for each of separated light beams, so that for each of the separated light beams of R, G, and B, a charge latent image is formed.
When photo-modulation material is used for the recording layer 12, the photo-modulation layer reacts to an electric field, so that an image is recorded as a change in optical characteristic of the photo-modulation layer.
However, there is a problem that the resolution decreases and thus, a normal color separation is difficult because an electro-magnetic radiation beam from the object 28 is color-separated and then enters the carrier generation layer 22a through the carrier transport layer 22b whose a thickness ranging from several micron meters to tens micron meters.
Moreover, there is a possibility that a sensitivity of the carrier generation layer at a specific band would decrease because there is a spectral transmission factor characteristic of the carrier transport layer 22b.